室温下Pt电极上CO的脱附机理

利用流动电解池与电化学原位红外光谱技术研究了温度和阴离子竞争吸附等因素对室温下Pt电极上COad的脱附机理与动力学的影响.研究表明当溶液中有Cl-或硫酸根等离子时,室温下未观察到COad从电极表面脱附.但是当溶液相存在与COad的吸附能相当甚至比之更大的粒子如CO或CN-时,COad可以被取代而从电极表面脱附.红外光谱表明吸、脱附过程中CN-ad与COad的红外谱带强度存在反线性的关系,而且变温实验估算得到COad的脱附能垒小于40kJmol-1,该脱附能垒远比CO的吸附能（〉60kJmol-1）小.上述结果进一步验证了室温下COad在Pt电极上的脱附不是热激发脱附.据此结果,本文详细地讨论了我们早先提出的吸附驱动的脱附机理的历程与能量来源.

The mechanism of room temperature CO desorption from Pt electrode

The mechanism and kinetics of CO desorption from Pt electrode has been studied by electrochemical in-situ infrared spectroscopy combined with a flow cell.The results reveal that at room temperature COad desorption can only be detected in solutions containing CO or CN-whose adsorption energy at Pt electrode is comparable or higher than that of COad,but not in solutions with species like Cl-or sulfate.A reciprocal linear relationship between the IR band intensity of COad and CN-ad is observed during the CN--COad displacement process.The activation energy for this process is found to be below 40 kJ/mol from temperature-dependent measurements,which is much smaller than the CO adsorption energy at Pt surface（60 kJ/mol）.The results further supports the adsorption driven desorption mechanism we proposed in our recent study,the detailed mechanism for such processes and the associated energy transfer are discussed.